Birds
February 24, 2011
Objectives
• Identify the characteristics of birds
• Identify the adaptations birds have for flight
• Explain how birds reproduce and develop
Bird characteristics
• Feathers
• Scales
• Lay eggs
Bird eggs
• Amniotic eggs with shells
• Shell made of calcium carbonate (same
material as seashells, limestone, and marble)
• Egg fertilized internally before shell forms
• Female lays eggs in some form of nest
• Group of eggs is called a clutch
• One or both parents incubate eggs and young
birds are cared for by one or both parents
Flight adaptations
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Hollow but strong skeleton
Wings
Feathers
Strong flight muscles
Efficient respiratory system
Well developed eyesight
Tremendous amounts of energy
Hollow bones
• Many bones joined together to provide extra
strength and stability
• Hollow bones filled with air
• Large sternum
• Spine supports tail feathers for steering and
balancing
Feathers
• Birds are only animals with feathers
• 2 types of feathers
– Contour feathers
– Down feathers
• Contour Feathers- strong lightweight feathers
that give birds their coloring and shape and
that are used for flight
Feathers
• Down Feathers- soft, fluffy feathers that
provide an insulating layer next to the skin of
adult birds and that cover the bodies of young
birds
• Birds are endotherms
• Feathers allow birds to maintain constant
internal temperature
• Feathers grow from follicles
Feathers
• Birds have an oil gland that allows them to
keep feathers healthy in a process called
preening
• Preening- process in which a bird rubs oil from
an oil gland over its feathers to condition
them
Wings
• Not all birds fly
• Wings are attached to chest muscles
• Curved on top and flat or slightly curved on
bottom
• Air pressure greater on bottom than on top
creating lift
• Penguins use wings to swim and ostrich use
wings for balance
Digestive System
• Eat high energy foods like nuts, seeds, nectar,
insects, and meat
• Food is broken down quickly
• Food moves into crop for storage, then to
stomach, then to gizzard for grinding, then to
the intestine
Respiratory System
• 2 lungs
• Each lung connected to an air sac
• Birds receive oxygen when they inhale and
exhale (unique to birds)
Circulatory System
• Heart, arteries, capillaries, veins
• 4 chambered heart which is large for their
bodies
• Oxygen filled blood is kept separate from
carbon dioxide filled blood
• Rapid heart beats
Importance of birds
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Source of food
Pets
Control pests
Flower pollinators
Can be pests
Carry disease
Peacock
Chicken
Blue bird
Baby chickens
Sea Gull
American Bald Eagle
Assignment
• What type of feather helps birds maintain
their body temperature?
• Compare and contrast birds that fly and do
not fly
• Why do most birds eat nuts, berries, insects,
nectar or meat but not grass or leaves.